A Model of the Neural Mechanisms Underlying Multisensory Integration in the Superior Colliculus

Perception ◽  
10.1068/p5842 ◽  
2007 ◽  
Vol 36 (10) ◽  
pp. 1431-1443 ◽  
Author(s):  
Benjamin A Rowland ◽  
Terrence R Stanford ◽  
Barry E Stein
Keyword(s):  
Superior Colliculus ◽  
Computational Model ◽  
Multisensory Integration ◽  
Neural Mechanisms ◽  
Specific Component ◽  
Algebraic Form ◽  
Sensory Inputs ◽  
Midbrain Structure ◽  
Cat Superior Colliculus

Much of the information about multisensory integration is derived from studies of the cat superior colliculus (SC), a midbrain structure involved in orientation behaviors. This integration is apparent in the enhanced responses of SC neurons to cross-modal stimuli, responses that exceed those to any of the modality-specific component stimuli. The simplest model of multisensory integration is one in which the SC neuron simply sums its various sensory inputs. However, a number of empirical findings reveal the inadequacy of such a model; for example, the finding that deactivation of cortico-collicular inputs eliminates the enhanced response to a cross-modal stimulus without eliminating responses to the modality-specific component stimuli. These and other empirical findings inform a computational model that accounts for all of the most fundamental aspects of SC multisensory integration. The model is presented in two forms: an algebraic form that conveys the essential insights, and a compartmental form that represents the neuronal computations in a more biologically realistic way.

scholarly journals Recurrent Antitopographic Inhibition Mediates Competitive Stimulus Selection in an Attention Network

2011 ◽  
Vol 105 (2) ◽  
pp. 793-805 ◽  
Author(s):  
Dihui Lai ◽  
Sebastian Brandt ◽  
Harald Luksch ◽  
Ralf Wessel
Keyword(s):  
Optic Tectum ◽  
Visual Pathway ◽  
Neural Mechanisms ◽  
Stimulus Selection ◽  
It Projects ◽  
Sensory Inputs ◽  
Surround Inhibition ◽  
Input Layer ◽  
Midbrain Structure ◽  
Constrained Model

Topographically organized neurons represent multiple stimuli within complex visual scenes and compete for subsequent processing in higher visual centers. The underlying neural mechanisms of this process have long been elusive. We investigate an experimentally constrained model of a midbrain structure: the optic tectum and the reciprocally connected nucleus isthmi. We show that a recurrent antitopographic inhibition mediates the competitive stimulus selection between distant sensory inputs in this visual pathway. This recurrent antitopographic inhibition is fundamentally different from surround inhibition in that it projects on all locations of its input layer, except to the locus from which it receives input. At a larger scale, the model shows how a focal top-down input from a forebrain region, the arcopallial gaze field, biases the competitive stimulus selection via the combined activation of a local excitation and the recurrent antitopographic inhibition. Our findings reveal circuit mechanisms of competitive stimulus selection and should motivate a search for anatomical implementations of these mechanisms in a range of vertebrate attentional systems.

Ultrastructure of developing visual cortical synapses in the cat superior colliculus

1991 ◽  
Vol 49 ◽  
pp. 156-157
Author(s):  
Caroline A. Miller ◽  
Laura L. Bruce
Keyword(s):  
Superior Colliculus ◽  
Phosphate Buffer ◽  
Receptive Fields ◽  
Visual Cortical Area ◽  
Cortical Synapses ◽  
Visual Cortical ◽  
And Function ◽  
Phosphate Buffered Saline ◽  
The Brain ◽  
Cat Superior Colliculus

The first visual cortical axons arrive in the cat superior colliculus by the time of birth. Adultlike receptive fields develop slowly over several weeks following birth. The developing cortical axons go through a sequence of changes before acquiring their adultlike morphology and function. To determine how these axons interact with neurons in the colliculus, cortico-collicular axons were labeled with biocytin (an anterograde neuronal tracer) and studied with electron microscopy.Deeply anesthetized animals received 200-500 nl injections of biocytin (Sigma; 5% in phosphate buffer) in the lateral suprasylvian visual cortical area. After a 24 hr survival time, the animals were deeply anesthetized and perfused with 0.9% phosphate buffered saline followed by fixation with a solution of 1.25% glutaraldehyde and 1.0% paraformaldehyde in 0.1M phosphate buffer. The brain was sectioned transversely on a vibratome at 50 μm. The tissue was processed immediately to visualize the biocytin.

scholarly journals Dynamic modulation of visual and electrosensory gains for locomotor control

2016 ◽  
Vol 13 (118) ◽  
pp. 20160057 ◽  
Author(s):  
Erin E. Sutton ◽  
Alican Demir ◽  
Sarah A. Stamper ◽  
Eric S. Fortune ◽  
Noah J. Cowan
Keyword(s):  
Augmented Reality ◽  
Multisensory Integration ◽  
Sensorimotor Integration ◽  
Sensory Conflict ◽  
Dynamic Modulation ◽  
Sensory Inputs ◽  
Locomotor Control ◽  
Eigenmannia Virescens ◽  
Future Work ◽  
Perceptual Weights

Animal nervous systems resolve sensory conflict for the control of movement. For example, the glass knifefish, Eigenmannia virescens , relies on visual and electrosensory feedback as it swims to maintain position within a moving refuge. To study how signals from these two parallel sensory streams are used in refuge tracking, we constructed a novel augmented reality apparatus that enables the independent manipulation of visual and electrosensory cues to freely swimming fish ( n = 5). We evaluated the linearity of multisensory integration, the change to the relative perceptual weights given to vision and electrosense in relation to sensory salience, and the effect of the magnitude of sensory conflict on sensorimotor gain. First, we found that tracking behaviour obeys superposition of the sensory inputs, suggesting linear sensorimotor integration. In addition, fish rely more on vision when electrosensory salience is reduced, suggesting that fish dynamically alter sensorimotor gains in a manner consistent with Bayesian integration. However, the magnitude of sensory conflict did not significantly affect sensorimotor gain. These studies lay the theoretical and experimental groundwork for future work investigating multisensory control of locomotion.

scholarly journals What does a neuron learn from multisensory experience?

2015 ◽  
Vol 113 (3) ◽  
pp. 883-889 ◽  
Author(s):  
Jinghong Xu ◽  
Liping Yu ◽  
Terrence R. Stanford ◽  
Benjamin A. Rowland ◽  
Barry E. Stein
Keyword(s):  
Superior Colliculus ◽  
Early Life ◽  
Life Experience ◽  
Sensory Experience ◽  
Rearing Environment ◽  
Early Life Experience ◽  
Environmental Events ◽  
Cat Superior Colliculus ◽  
Maturational Process ◽  
Multisensory Experience

The brain's ability to integrate information from different senses is acquired only after extensive sensory experience. However, whether early life experience instantiates a general integrative capacity in multisensory neurons or one limited to the particular cross-modal stimulus combinations to which one has been exposed is not known. By selectively restricting either visual-nonvisual or auditory-nonauditory experience during the first few months of life, the present study found that trisensory neurons in cat superior colliculus (as well as their bisensory counterparts) became adapted to the cross-modal stimulus combinations specific to each rearing environment. Thus, even at maturity, trisensory neurons did not integrate all cross-modal stimulus combinations to which they were capable of responding, but only those that had been linked via experience to constitute a coherent spatiotemporal event. This selective maturational process determines which environmental events will become the most effective targets for superior colliculus-mediated shifts of attention and orientation.

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